Automatic fire-alarm.



F. W. LINDEMANN.

AUTOMATIC FIRE ALARM.

APPLICATION FILED AUG.24. 1916.

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FREDERICK W. LINDEMANN, OF ST. PAUL, MINNESOTA.

AUTOMATIC FIRE-ALARM.-

Specification of Letters Patent.

Patented June 12, 191?.

Application filed August 24, 1916. Serial No. 116,686.

1 0 all whom it may concern:

Be it known that I, FREDERIOK W. LiNpE- MANN, a citizen of the United States, residing at St. Paul, in the county of Ramsey and State of Minnesota, have invented certain new and useful Improvements in Auto inatic F ire-Alarms and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appert'ains to make and use the same.

This invention relates to new and useful improvements in fire alarms of the automatic type.

The object of the invention is to provide a simple, cheap and efficient device of this character which may be easily attached to a support and when the temperature where it is located reaches a predetermined height, a plunger carrying a firing pin will be re leased and automatically produce a detonation by striking and firing a blank cartridge mounted in the path of the plunger.

\Vith the foregoing and other objects in view, which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed may be made within the scope of what is claimed without departing from the spirit of the invention.

In the accompanying drawings Figure 1 represents a bottom plan view of this improved fire alarm with the parts ar ranged in position ready for use;

Fig. 2 is a side elevation thereof;

Fig. 3 is a longitudinal vertical section;

Fig. 4 is a transverse section taken on the line 44 of Fig. 3.

Fig. 5 is a similar View taken on line 55 of Fig. 3; and

Fig. 6 is a plan view of the blank from which the casing is made.

In the embodiment illustrated, the invention includes a tubular shell 1 preferably cylindrical in form and having apertured ears 2 extending longitudinally from its opposite ends preferably in alinement with one of its side walls to adapt the device to lie flat against the ceiling or other support and to be secured thereto by fastening elements inserted through the apertures in said ears.

A blank cartridge support is shown in the form of a reduced shouldered chamber 3 arranged at the front end of the front of the cylinder 1 and is designed to receive a blank cartridge 4: which is of ordinary construction and the flange 5 thereof is designed to engage the shoulder at the'inner end of the chamber 3. A slot 6 extends throughout the greater portion ofthe length of the shell and is designed for a purpose soon to be described.

A plate or strip 7 is arranged at the rear end of the casing 1 and extends across the end thereof and has an upstanding lug 8 projecting through the slot 6 and deflected rearwardly to form a hook.

The lower end of said strip is removably mounted in an opening 8 formed in shell 1 opposite slot 6.

The casing 1 is made from a sheet metal blank stamped out in the form shown in Fig. 6, the wings A and B of Which are rolled toward each other to form a cylinder 1 with the cartridge chamber 3, the edges thereof being soldered together as shown at C throughout the length of the chamber 3 and spaced apart throughout the casing 1 to form the slot 6.

A plunger 9 is mounted to reciprocate in the casing 1 and is provided at its rear with a shank or stem 10 around which is arranged a coiled spring 11 which bears at one end against the plate 7 and at its other end against the rear face of the plunger 9 and is designed to exert its tension normally to project the plunger toward the front end of the casing.

A hook-shaped finger 12 extends upwardly from the plunger 9 through the slot 6 in the casing 1 with the beak of its hook preferably extending toward the front and which is designed for a purpose tobe described. A firing pin 13 projects from the front face of the plunger 9 and is positioned to aline with the cap of the cartridge 4: which is arranged in the path of theplunger.

A sectional strip 14 is provided at its op-' posite ends with openings 15 which are designed to engage the fixed hook-shaped lug 8 at the rear of the casing l and the hookshaped finger 12 carried by the plunger and is of such a length that when so engaged, the plunger will be held in retracted position and the spring 11 contracted between the'plunger and the plate 7 so that when the plunger is released, the spring will exert its tension to project it forwardly with con-a siderable force. The'sections of the strip 14 are arranged in superposed, overlapping relation and are held together by fusible pins 16 which will fuse at a relatively low temperature so that when a pre-determined temperature has been reached and the pins melted, the two parts or sections of the strip 14 will separate and, permit the plunger under the influence of the spring 11 tomove forward and cause its firin pin 13 to penetrate the cap of the cartridge 4' and thus Sound an alarm.

Any desired number of these. devices may be used in a single room and the connecting means between the sections of the strips 14 may be fusible at different degrees of heat so that as the temperature rises, repeated alarms will be given.

1. An automatic fire alarm comprising a longitudinally slotted casing provided with attaching means, a spring pressed plunger mounted in said casing and carrying a firing pin at its front .end, means for supportlng a blank cartridge in, the path of said pm, a finger projecting from said plunger through the slot in said casing, a fixed upstanding lug at the rear of said slot, a sectional strip provided at its ends with openings, one of which is engaged with said lug and the other with said plunger finger, whereby the plunger spring is held normally in contracted position, the sections of the strip being secured together by a fusible connection.

2. An automatic fire alarm comprising a cylindrical casing having apertured ears at its opposite ends, a cartridge support arranged at the front end of said casing, said casing having a slot therein, a plunger mounted in said casing to move in the same direction as said slot and having a hookshaped finger projecting through said slot, a shank carried by said plunger, a coiled spring encircling said shank and bearing at one end against said plunger, a plate in said casing against which the other end of said coiled spring bears, a hook-shaped lugextending from said plate through said slot, a firing pin carried by said plunger and positioned to engage a blank cartridge adapted to be mounted on said support, and a sectional strip provided at its ends with openings, one of which is engaged with said lug and the other with said plunger finger, said strip being of a length sufiicient to hold the plunger retracted against the tension of its spring, the sections of said strip being arranged in overlappin relation and secured together by aconnection fusible at a predetermined temperature.

3. An automatic fire alarm comprising a sheet metal blank rolled to form a casing with its side edges spaced apart to form a longitudinal slot and one end'reduced and shouldered to form a cartridge chamber, attaching elements at the ends of said casing, a strip extending across the rear end of the casing and having one end removably engaged therewith and its other end extending through said slot, a spring pressed plunger mounted in said casing, a firing pin carried by the front end of said plunger, a finger projecting from said plunger through the slot in said casing, a shank extending from its rear face, a coiled spring on said shank bearing 'at one end against the plunger and at its other end against said strip, and a connecting and restraining element engaged with said finger and strip and having a fusible portion between its ends;

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses. p

FREDERICK W. LINDEMANN.

Witnemes:

HARVEY J. PETER, WM. J. PETER. 

